There is a board at the entrance: "stalactites grow quickly, 1mm per 3 years." Surprisingly quick! I like this very much in Japan - one can learn a lot just by reading the information posted everywhere. Like, names of birds and flowers. I once found a whole list of tree names in a public toilet. That is lovely.
The name of the cave in kanji - Gyokusendo:
化石 kaseki is fossil. And 石 ishi means stone.
There is a bone of a deer extinct 15,000 years ago. In the northern part of the country, there is less information in English. And I noticed many bilingual signs in Hokkaido - Japanese and Russian. Though, the message is somewhat clear even from the nice drawings always there. Like this deer and a bone.
The largest stalagmite in Japan - 2.5 m high. With 1 mm per 3 years, imagine the time required to form such wonders.
"Gathered Drapes - It is rare to see this shape hanging from the ceiling and we are very proud of it." We, so typical Japanese. I am always impressed with their feeling of patriotism. "It takes about 200,000 years to grow to this scale."
An aquarium inside the cave - Japanese people love fish so much. Though I have seen one aquarium inside Postojna/Postojnska Cave in Slovenia. They have a rare fish there, the human fish. A trogloditic amphibian.